Structure enhancement of energetic materials: A theoretical study of the arylamines to arylpentazoles transformation

Abstract

A theoretical study of the effect of amines-to-pentazoles transformation on the detonation performance is reported in this paper. A quantitative description of the latter is performed for the general case according to our recently developed compositional criterion evaluation algorithm. It is shown that increments of crystal density and enthalpy of formation are both positive meaning a higher detonation performance of the resulting pentazoles. Since the known arylpentazoles are thermally unstable compounds, a simple descriptor of the thermal stability was revealed (R2 = 0.98), which allowed modeling of new pentazoles with expected thermal stability up to 77 °C. Five the most thermally stable structures were then analyzed using high-level first-principles calculations, which provided negative values of the detonation energy for all ionic compounds; this may allow proposing them as safe gas-forming agents. Meanwhile, the relative gain in detonation energy caused by the studied reaction is always positive and can reach 600%. Thus, we have shown that amines-to-pentazoles transformation is an effective tool for enhancing detonation properties when the resulting compound satisfies the thermal stability criterion. Also, we have demonstrated that aromatic/heterocyclic pentazoles may be considered as self-sufficient materials without further modifications by detachment of the aromatic ring.